Absence of the tag polymorphism for the risk haplotype HLA-DR2 for multiple sclerosis in Wixárika subjects from Mexico.

The HLA-DRB1*15:01 allele has a demonstrated risk for the development of multiple sclerosis (MS) in most populations around the world. The single nucleotide polymorphism (SNP) rs3129934 is found in linkage disequilibrium with the risk haplotype formed by the HLA-DRB1*15:01 and HLA-DQB1*06:02 alleles, and it is considered a reliable marker of the presence of this haplotype. Native Americans have a null or low prevalence of MS. In this study, we sought to identify the frequency of rs3129934 in the Wixárika ethnic group as well as in Mestizo (mixed race) patients with MS and in controls from western Mexico. Through real-time polymerase chain reaction (PCR) using TaqMan probes, we analyzed the allele and genotype frequencies of rs3129934 in Mestizo individuals with and without MS and in 73 Wixárika subjects from the state of Jalisco, Mexico. The Wixárika subjects were homozygote for the C allele of rs3129934. The allele and genotype frequency in Mestizos with MS was similar to that of other MS populations with Caucasian ancestry. The absence of the T risk allele rs3129934 (associated with the haplotype HLA-DRB1*15:01, HLA-DQ1*06:02) in this sample of Wixárika subjects is consistent with the unreported MS in this Amerindian group, related to absence of such paramount genetic risk factor.